1. Technical Field
The present disclosure relates to a communication apparatus and a communication method. For example, the present disclosure relates to a communication apparatus that performs communication by using a plurality of communication paths.
2. Description of the Related Art
Nowadays, with the increasing functionality of mobile terminals and the increasing densities of video content, video files with high image qualities and large-size files are also increasingly transmitted and received by mobile terminals. In such an environment, a communication terminal is generally required to transmit/receive (communicate) a large-size file to/from another party's communication terminal at high speed.
Short-range wireless communication using a millimeter wave band (hereinafter referred to as “millimeter wave communication”) has attracted attention as a method for high-speed communication. Millimeter wave communication is a communication method that can realize gigabit throughput or higher. For communication between mobile terminals, millimeter wave communication is also expected to play a role of replacing infrared communication or reducing traffic in public communication networks.
In IEEE802.11ad (60 GHz), which is a Wireless Fidelity (WiFi) standard for millimeter wave communication, Fast Session Transfer (FST) has been standardized. FST is a system that performs seamless switching on the order of milliseconds between a millimeter wave communication and a wireless local area network (LAN) (5 GHz/2.4 GHz) communication (i.e., switching of a communication using 60 GHz to a communication using 5 GHz/2.4 GHz or switching from a communication using 5 GHz/2.4 GHz to a communication using 60 GHz). FST has attracted attention as a standard for compensating for high-speed communication, which is a feature of the millimeter wave communication (see, for example, “Part 11: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) Specifications Amendment 3: Enhancements for Very High Throughput in the 60 GHz Band”, IEEE Computer Society IEEE Std 802.11ad, Dec. 28, 2012, P396-P407 (this document is referred to as “Non-Patent Document 1” hereinafter).
As a system for transmitting a plurality of control packets between two communication apparatuses, a communication system as described below is known (see, for example, Japanese Unexamined Patent Application Publication No. 2008-177754 (hereinafter referred to as Patent Document 1)).
The communication system disclosed in Patent Document 1 has two transmission paths between first and second terminal stations and a base station. The two transmission paths are constituted by a wireless communication path (a transmission path A) and a communication path (a transmission path B) using a power line. By using the two transmission paths, the first terminal station or the second terminal station and the base station transmit data packets therebetween in a downlink direction and transmit control packets in an uplink direction. The downlink direction is a direction from the base station to the first or second terminal station. The uplink direction is a direction from the first or second terminal stations to the base station.
Patent Document 1 discloses two transmission modes, that is, a high-speed transmission mode and a high-quality transmission mode. The high-speed transmission mode is a mode in which transmission packets (data packets) are distributed to the two transmission paths, and is used for transmission in the downlink direction. The high-quality transmission mode is a mode in which even when the quality of communication in one of the transmission paths is poor, the other transmission path is used to complement the communication. The high-quality transmission mode is mainly used in the uplink direction.
In the technology disclosed in Patent Document 1 or Non-Patent Document 1 do not sufficiently consider a communication situation at 60 GHz for switching of the communication path. Consequently, the accuracy of switching the communication path is insufficient.